AMC 8 1985 Problem 21
AMC8 1985 年第 21 题
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Mr. Green receives a 10% raise every year. His salary after four such raises has gone up by what percent?
Mr. Green 每年获得 10% 的加薪。经过四次这样的加薪后，他的工资上涨了百分之多少？
- A. / 小于 40%
- B.40%
- C.44%
- D.45%
- E. / 大于 45%
正确答案 · Correct Answer
E
解析 · Solution
Solution 1
Each year, Mr. Green's salary is multiplied by 1.1. Therefore, after 4 years, his salary will be times his current salary, for a total increase of 46.41%, which is more than 45%.
Suppose Mr. Green's salary is originally 100. After 1 year, his salary will be 110. After 2 years, his salary will be 121. After 3 years, his salary will be 133.10. After 4 years, his salary will be 146.41, which is 1.4641 times his original salary. This is a 46.41% increase, so the answer is more than 45%.
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